1. Technical Field
The present invention relates to a light source device and a projector.
2. Related Art
Heretofore, a light source device having an electrodeless lamp has been known as a light source device used for a projector. In such an electrodeless lamp, a pair of waveguide bodies made of metallic wires is provided in an electric discharge tube in which a light emitting material that emits light by an electromagnetic field of microwaves is encapsulated, and the light is emitted by concentrating the electromagnetic field generated at a gap between both ends of the waveguide bodies. JP-A-2007-115534 (patent document 1) is an example of the related art. By generating the light at the gap between the waveguide bodies, electric power can be efficiently transmitted and the advantage is achieved that a light emission volume can be reduced since the light emission is taken place at the gap. However, in an actual case, there is a problem that the waveguide body acts as an antenna so that the light emission efficiency at the gap is not improved or the emission of light is not stable.
Meanwhile, some lamps in which an electromagnetic field is concentrated by using a cylindrical resonator are proposed. For example, JP-A-2007-102194 (patent document 2) discloses a structure of a device in which a lamp having a discharge concentrator is disposed in a resonating cavity and electromagnetic energy is supplied to the resonating cavity.
In the device described in the patent document 2, leakage of the electromagnetic energy is prevented by the resonance cavity. However, since the device is structured such that the electromagnetic energy is not forcedly concentrated to the discharge concentrator, the energy is wasted. Therefore, in a case where light is emitted by a lamp by using a resonator, it is important to use a method for efficiently concentrating microwaves.